In an organic electroluminescent display device, a component for protecting the light-emitting layer and layers around the light-emitting layer is usually provided in order to prevent the deterioration thereof. For example, it is known that when an organic electroluminescent display device includes a substrate plate and a light-emitting layer formed thereon, a sealing material layer is disposed on the light-emitting layer, and a barrier layer for interfering with the transmission of moisture, oxygen, and the like is further disposed thereon.
As such a barrier layer, a barrier layer having a multilayer structure with a substrate for forming the barrier layer is known. That is, a barrier layered body containing a substrate and a barrier layer disposed on this substrate is prepared, and then the prepared barrier layered body is incorporated into an organic electroluminescent display device. A glass substrate has often been used as the substrate of the barrier layered body. However, it is recently proposed to use a substrate film made of a resin as the substrate (see Patent Literatures 1 to 3).
Furthermore, an organic electroluminescent display device may be provided with a circularly polarizing plate in order to reduce the reflection of outside light on the display surface. As such a circularly polarizing plate, a film including a combination of a linear polarizer and a ¼ wave plate as a phase difference film is generally used. As this ¼ wave plate, a broadband ¼ wave plate including a combination of a ¼ wave plate and a ½ wave plate has been proposed (see Patent Literatures 4 to 9). According to this broadband ¼ wave plate, retardation of an approximately quarter wavelength can be attained with light in an ideally wide wavelength range. Therefore, a circularly polarizing plate that can reduce reflection of outside light in a wide wavelength range can be achieved. In addition, there is known a technology of a phase difference film in which the slow axis direction exists in an oblique direction which is neither orthogonal nor parallel to the width direction of the film among the in-plane directions of the film, as disclosed in Patent Literature 10.